Protective device of the floating barrier type

ABSTRACT

A protective device ( 1 ) of the “floating barrier” type for preventing a floating body from colliding with a construction includes a barrier element ( 2 ) consisting of a cable provided with floats ( 4 ), each of the two ends ( 2   a ) of which cable is connected to a respective one of the posts ( 3 ), and at least one of which ends is connected to the respective one of the posts ( 3 ) via an energy-dissipation system ( 5 ). The energy-dissipation system ( 5 ) advantageously includes: at least one chain having a segment that is folded in half, being made up of links that are connected together in pairs by breakable ties; and at least one spring member.

The present invention relates to a protective device of the “floatingbarrier” type for preventing a moving floating body or obstacle (inparticular a watercraft or a vessel) from colliding with a constructionin such a manner as to protect said construction from any impact.

Barriers having similar purposes have been put in place on canals orrivers, using jacks or anchor systems dragging on the water bottom. Suchdevices have operating constraints, high implementation costs, andtechnical limitations.

Similarly, a device for stopping submarines and torpedoes is describedin Document U.S. Pat. No. 1,151,607.

That device includes, in particular, an outer defense structurecomprising an immersed rigid barrier that is carried by buoys and thatis secured between two posts via intermediate elements in the form offlexible ties.

That device aims to destroy the body that it is to be retained. It doesnot enable said body to be captured while also preserving its structuralintegrity (or at least while also limiting damage to it).

The present invention provides a novel structure for a protective deviceof the “floating barrier” type.

This protective device is of the type comprising a barrier element thatis mounted between two anchoring piles or posts and that is associatedwith a plurality of floats floating on the surface of the water.

According to the invention, the barrier element comprises a cableprovided with the floats; said cable has two ends, each of which isconnected to a respective one of the posts; and at least one of saidends of the cable is connected to the respective one of said posts viaan energy-dissipation system.

Such a protective device offers particularly effective absorption of thekinetic energy of a floating body, thereby protecting a constructionparticularly effectively from any impact by said floating body.

This protective device also makes it possible not to damage the retainedfloating body, e.g. the hull of a boat or of a ship, and to keep itafloat some distance away from the construction to be protected.

Advantageously, each of the two ends of the cable is connected to therespective one of the posts via an energy-dissipation system.

In a preferred embodiment, the or each of the energy-dissipation systemscomprises i) at least one chain having a segment that is folded in half,being made up of links that are connected together in pairs by breakableties; and ii) at least one spring member.

The spring member is suitable for being moved between a restconfiguration and a deformed configuration; and said spring member isadvantageously associated with means for delivering a braking forcedesigned to limit the speed at which the spring member moves from saiddeformed configuration to said rest configuration.

This characteristic makes it possible to avoid the links of the chainmoving at excessive speed that might generate a dynamic effect conduciveto causing a plurality of breakable ties to break simultaneously.

The spring member then advantageously consists of a compression springsuitable for being moved in compression and in decompression; saidspring member is encased in a casing enclosing a piston that is movablein translation and that is made up of a head and of a rod, so as to forma damper assembly comprising the casing, the piston, and the springmember; the casing and the piston head form two surfaces holding saidspring member captive; and the casing and the piston rod are providedwith respective fastening points enabling them to be connected to thecable, to the chain, or to the post, as applicable.

The casing is then advantageously filled with liquid, advantageouslywater; and the piston head is provided with openings enabling the liquidto flow through, so as to deliver a braking force during the movementsin compression and in decompression.

In a preferred embodiment, the chain of the energy-dissipation system isinterposed between two spring members.

A first damper assembly is then connected at one end to the cable and atthe other end to the chain, and a second damper assembly is connected atone end to the post and at the other end to the chain.

Also in the preferred embodiment, the breakable ties are constituted bymetal ties or by ties of the rope type, e.g. made of synthetic polymer.

According to another characteristic, the energy-dissipation system isadvantageously connected to the post via a collar mounted to move invertical translation along said post, in order to enable the cable toremain floating in the event that the level of the water varies.

The present invention also provides an energy-dissipation systemcomprising:

-   -   at least one chain having a segment that is folded in half,        being made up of links that are connected together in pairs by        breakable ties; and    -   at least one spring member.

The spring member is then suitable for being moved between a restconfiguration and a deformed configuration; and said spring member isadvantageously associated with means for delivering a braking forcedesigned to limit the speed at which the spring member moves from saiddeformed configuration to said rest configuration.

The spring member then advantageously consists of a compression springsuitable for being moved in compression and in decompression; saidspring member is encased in a casing enclosing a piston that is movablein translation and that is made up of a head and of a rod, so as to forma damper assembly comprising the casing, the piston, and the springmember; the casing and the piston head form two surfaces holding saidspring captive; and the casing and the piston rod are provided withrespective fastening points enabling them to be connected to the cable,to the chain, or to the pile, as applicable.

In a preferred embodiment, the casing is then filled with liquid, whichis advantageously constituted by water, and the piston head is providedwith openings enabling the liquid to flow through.

Also in a preferred embodiment, the chain of the energy-dissipationsystem is interposed between two spring members.

The present invention is further illustrated, in a manner that is in noway limiting, by the following description given with reference to theaccompanying drawing, in which:

FIG. 1 is a general diagrammatic view of the protective device of theinvention, in its context as a floating barrier;

FIG. 2 is a diagrammatic view of one of the energy-dissipation systemsequipping the protective device shown in FIG. 1;

FIG. 3 is a diagrammatic view of one of the damper assemblies making upthe energy-dissipation system shown in FIG. 2; and

FIG. 4 is an end-on detail view of the head of a piston that is movablein translation and that equips the damper assembly shown in FIG. 3.

The protective device 1 shown in FIG. 1 is of the “floating barrier”type.

The protective device 1 is designed to retain a moving floating body(not shown), e.g. a watercraft or vessel, so as to prevent that bodyfrom colliding with a construction (not shown). For example, it isdesigned to be installed across a river for the purpose of protecting aconstruction situated downstream from it.

Conversely, and advantageously, the protective device 1 allows floatingobstructions to pass through it so that they do not form jams.

For this purpose, the protective device 1 of the invention includes abarrier element 2, constituted by a cable in this example, that isarranged, in this example, to form a barrier across a river C and toretain the moving floating body (not shown).

The cable 2 is mounted, advantageously in tensioned or semi-tensionedmanner, between two piles or posts 3 for anchoring it at the riverbanks.

The cable 2 has two ends 2 a, each of which is connected to a respectiveone of the posts 3.

The cable 2 is advantageously designed to extend horizontally, or atleast approximately horizontally, between the posts 3.

Each post 3 advantageously has a cross-section that is constant, or atleast approximately constant, over its entire height. Each post 3 isanchored into the ground S.

The cable 2 is associated with a plurality of floats 4 floating on thesurface of the water E.

The floats 4 are suitably distributed over the length of the associatedcable 2.

In this example, the floats 4 are of cylindrical shape, and theassociated cable 2 passes axially through each of them.

In order to absorb the kinetic energy of a floating body retained by theprotective device 1, each of the ends 2 a of the cable 2 is connected toa respective one of the posts 4 via an energy-dissipation system 5.

Each energy-dissipation system 5 is thus interposed between a respectiveone of the ends 2 a of the cable 2 and a respective one of the posts 3.

One of the energy-dissipation systems 5 is described below withreference to FIG. 2.

This energy-dissipation system 5 comprises an energy-dissipation loop 6that is interposed between two spring members 7.

The energy-dissipation loop 6 consists of a chain 8 having a segmentfolded in half (in the general shape of a U) and made up of a pluralityof links 9 that are connected together in pairs by breakable ties 10.

The breakable ties 10 form “fuses”, each of which interconnects twospaced-apart links 9.

The length of a breakable tie 10 is less than the length of the chain 8between the two associated links 9 so that, when the protective device 1is subjected to a thrust force generated by the moving body that is tobe stopped, the breakable tie 10 breaking (or at least deforming)absorbs at least a fraction of the energy generated by the moving body.

In order to limit dynamic effects that are described in more detailbelow, the breakable ties 10 are chosen to be made of a material havinga certain amount of elasticity.

The breakable ties 10 are advantageously made of a metal material or ofrope (e.g. rope made of synthetic polymer), having a predefined breakingstrength.

In this example, each spring member 7 consists of a compression springsuitable for being moved in compression (from a rest configuration to adeformed configuration) and in decompression (from a deformedconfiguration to a rest configuration).

In this example, each spring member 7 is engaged in a device 12 in theform of a hydraulic jack (FIG. 3) designed to limit the speed of itsmovements in compression and in decompression.

As shown in FIG. 3, this device in the form of a jack 12 comprises acasing 13 defining an internal volume 14 enclosing the spring member 7,and a piston 15 that is movable in translation.

The spring member 7 associated with the casing 13 and with the piston 15form an assembly 16 referred to below as a “damper assembly”.

In this example, the casing 13 consists of a cylindrical tube, so thatthe internal volume 14 is also of generally cylindrical shape.

The piston 15 that is movable in translation is made up of:

-   -   a disk-shaped head 15 a subdividing the internal volume 14 into        two chambers 14 a and 14 b, a first chamber 14 a of which        contains the spring member 7; and of    -   a rod 15 b passing axially through the spring member 7 and said        first chamber 14 a.

The piston 15 is mounted to move in translation inside the internalvolume 14 and over its length.

The casing 13 and the piston head 15 a form two facing surfaces definingthe first chamber 14 a and for holding the spring 7 captive, which facesare designated respectively by references 17 and 18 in FIG. 3.

In order to brake the movements in compression and in decompression ofthe spring member 7, the internal volume 14 of the casing 13 is filledwith a liquid, which is advantageously constituted by water.

In addition, the piston head 15 a, against which one of the ends of thespring member 7 bears, is provided with through openings 19 (FIG. 4)allowing the liquid to pass through and to flow between the two chambers14 a and 14 b.

Thus, the piston 15 that is movable in translation creates two chambers14 a and 14 b between which liquid flows while its head 15 a is movingin translation. This liquid flow delivers a braking force that limits,in particular, the speed of the movement of the spring member 7 indecompression.

Finally, the casing 13 and the rod 15 b of the piston 15 that is movablein translation are provided with respective fastening points, referencedrespectively 20 and 21 in FIG. 3, enabling them to be connected to thecable 2, to the chain 8, or to the pile 3, as applicable.

These two fastening points 20 and 21 are advantageously opposite fromeach other axially/longitudinally.

Thus, in each energy-dissipation system 5, an “inner” first damperassembly 16 (remote from the pile 3) is mounted so that:

-   -   the fastening point 20 of its casing 13 is connected to the        cable 2; and    -   the fastening point 21 of the rod 15 b of its piston 15 is        connected to the chain 8.

An “outer” second damper assembly 16 (in the vicinity of the pile 3) ismounted so that:

-   -   the fastening point 20 of its casing 13 is connected to the        chain 8; and    -   the fastening point 21 of the rod 15 b of its piston 15 is        connected to the pile 3.

In an alternative embodiment, the inner damper assembly 16 and/or theouter damper assembly 16 is/are mounted so that the fastening points 20and 21 are secured the other way round from the configuration describedabove.

In an embodiment (not shown), the spring member or each of the springmembers may equally well consist of a traction spring.

The traction spring may be incorporated into a device in the form of ajack as described above with reference to FIG. 3, in order to deliver abraking force that limits, in particular, the speed of movement from thelengthened deformed configuration to the rest configuration.

In this example, the coupling to each anchoring post 3 is via a slidingcollar 25 (FIG. 1) suitable for travelling over the height of theassociated post 3.

This characteristic enables the cable 2 with floats 4 to floatcontinuously on the surface of the water E or just beneath the surfaceof the water E, regardless of the variations in the level of the surfaceof the water E.

In operation, when a floating body reaches the protective device 1 itexerts a thrust force on its cable 2.

The force of the moving body is transmitted from the cable 2 to theenergy-dissipation systems 5.

Firstly, the work delivered by the spring members 7 being moved incompression absorbs a fraction of the kinetic energy of the floatingbody to be stopped.

This movement in compression is obtained by the surfaces 17 and 18 thathold the spring member 7 captive moving closer together.

Since the spring members 7 have strokes that are limited compared withthe stopping distance of the floating body, the energy-dissipation loops6 enable the cable 2 between the posts 3 to lengthen progressively, andthey participate in dissipating the kinetic energy progressively.

For this purpose, when the spring members 7 come to the end of theirmovement in compression, continued traction on the energy-dissipationsystems 5 causes one of their breakable ties 10 to break, therebyreleasing a length enabling the spring members 7 to move indecompression.

The breakable ties 10 thus absorb a fraction of the kinetic energy ofthe moving body, so as to slow it down.

Advantageously, the speed of movement in decompression of the springmembers 7 should not be excessive, in particular in order to avoid thespeed at which the links 9 of the chain 8 are bust apart generating adynamic effect leading to a plurality of successive breakable ties 10all breaking simultaneously.

For this purpose, the movement of the spring members 7 is damped, inthis example, by the flow of liquid through the orifices 19 in theassociated piston head 15 a.

Once the movement in decompression is finished, the spring members 7 canstart to move in compression again due to the continued thrust on thecable 2, possibly accompanied by another breakable tie 10 breaking,depending on the kinetic energy remaining to be dissipated.

Movements in compression and in decompression of the spring members 7,which movements being separated by the breaking of successive breakableties 10, are repeated until the floating body stops.

The floating body is thus stopped, advantageously without suffering anydamage, and with it being kept afloat some distance away from theconstruction.

Merely by way of example, the protective device 1 advantageously has thefollowing characteristics:

-   -   the anchoring posts 3 serving to retain the cable 2 withstand a        horizontal force of about 100 metric tonnes (t);    -   each of the spring members 7 has a weight of greater than 300        kilograms (kg) and a diameter of about 50 centimeters (cm), and        presents a stroke of 24 cm for compression of 50 t;    -   the chain 2 has a minimum breaking strength of 130 t;    -   the breakable ties 10 have a minimum breaking strength of 50 t,        and that strength should not exceed 70 t; and    -   the cable 2 used has a minimum breaking strength of 200 t.

1. A protective device of the “floating barrier” type for preventing afloating body from colliding with a construction, which protectivedevice (1) comprises a barrier element (2) that is mounted between twoanchoring posts (3) and that is associated with a plurality of floats(4) designed to float on the surface of the water (E), said protectivedevice being characterized in that said barrier element (2) comprises acable provided with said floats (4), in that said cable (2) has two ends(2 a), each of which is connected to a respective one of said posts (3),and in that at least one of said ends (2 a) of said cable (2) isconnected to the respective one of said posts (3) via anenergy-dissipation system (5).
 2. A protective device according to claim1, characterized in that each of the two ends (2 a) of the cable (2) isconnected to the respective one of the posts (3) via anenergy-dissipation system (5).
 3. A protective device according to claim1, characterized in that each of the energy-dissipation systems (5)comprises: at least one chain (8) having a segment that is folded inhalf, being made up of links (9) that are connected together in pairs bybreakable ties (10); and at least one spring member (7).
 4. A protectivedevice according to claim 3, characterized in that the spring member (7)is suitable for being moved between a rest configuration and a deformedconfiguration, and in that said spring member (7) is associated withmeans (12, 13, 14, 15) for delivering a braking force designed to limitthe speed at which the spring member moves from said deformedconfiguration to said rest configuration.
 5. A protective deviceaccording to claim 4, characterized in that the spring member (7)consists of a compression spring suitable for being moved in compressionand in decompression, in that said spring member (7) is encased in acasing (13) enclosing a piston (15) that is movable in translation andthat is made up of a head (15 a) and of a rod (15 b), so as to form adamper assembly (16) comprising said casing (13), said piston (15) thatis movable in translation, and said spring member (7), which casing (13)and which piston head (15 a) form two surfaces (17, 18) holding saidspring member (7) captive, and which casing (13) and which piston rod(15 b) are provided with respective fastening points (20, 21) enablingthem to be connected to the cable (2), to the chain (8), or to the pile(3), as applicable.
 6. A protective device according to claim 5,characterized in that the casing (13) is filled with liquid, and in thatthe piston head (15 a) is provided with openings (19) enabling theliquid to flow through.
 7. A protective device according to claim 5,characterized in that the chain (8) of the energy-dissipation system (5)is interposed between two spring members (7).
 8. A protective deviceaccording to claim 7, characterized in that a first damper assembly (16)is connected at one end to the cable (2) and at the other end to thechain (8), and in that a second damper assembly (16) is connected at oneend to the post (3) and at the other end to the chain (8).
 9. Aprotective device according to claim 3, characterized in that thebreakable ties (10) are constituted by metal ties or by rope ties.
 10. Aprotective device according to claim 1, characterized in that theenergy-dissipation system (5) is connected to the post (3) via a collar(25) mounted to move in vertical translation along said post (3), inorder to enable the cable (2) to remain floating in the event that thelevel of the water (E) varies.
 11. An energy-dissipation system for aprotective device according to claim 1, comprising: at least one chain(8) having a segment that is folded in half, being made up of links (9)that are connected together in pairs by breakable ties (10); and atleast one spring member (7).
 12. An energy-dissipation system accordingto claim 11, characterized in that the spring member (7) is suitable forbeing moved between a rest configuration and a deformed configuration,and in that said spring member (7) is associated with means (12, 13, 14,15) for delivering a braking force designed to limit the speed at whichthe spring member moves from said deformed configuration to said restconfiguration.
 13. An energy-dissipation system according to claim 12,characterized in that the spring member (7) consists of a compressionspring suitable for being moved in compression and in decompression, andin that said spring member (7) is encased in a casing (13) enclosing apiston (15) that is movable in translation and that is made up of a head(15 a) and of a rod (15 b), so as to form a damper assembly (16)comprising said casing (13), said piston (15) that is movable intranslation, and said spring member (7), which casing (13) and whichpiston head (15 a) form two surfaces (17, 18) holding said spring (7)captive, and which casing (13) and which piston rod (15 b) are providedwith respective fastening points (20, 21) enabling them to be connectedto the cable (2), to the chain (8), or to the post (3), as applicable.14. An energy-dissipation system according to claim 13, characterized inthat the casing (13) is filled with liquid, and in that the piston head(15 a) is provided with openings (19) enabling the liquid to flowthrough.
 15. An energy-dissipation system according to claim 11,characterized in that the chain (8) of the energy-dissipation system (5)is interposed between two spring members (7).
 16. A protective deviceaccording to claim 2, characterized in that each of theenergy-dissipation systems (5) comprises: at least one chain (8) havinga segment that is folded in half, being made up of links (9) that areconnected together in pairs by breakable ties (10); and at least onespring member (7).
 17. A protective device according to claim 3,characterized in that the chain (8) of the energy-dissipation system (5)is interposed between two spring members (7).